One who was making fun of Chad Gadya that we say in Ashkenaz on the first night of Hag, and one of the guests jumped up and excommunicated him (Nidduy) - is his Nidduy proper? or did he act improperly and he himself is excommunicated?
Frightfully, the Chida seems to take quite a dim view of this heretic. After explaining how Chad Gadya is said by all of the Gedolim, and how by laughing about it, he is in fact making fun of all of them, the Chida pronounces that not only was the excommunication proper - he should also be fined.
The Chida finishes by stating that there are many fine explanations for the meaning of Chad Gadya. He even states that some great man (who he doesn't name) has written a book with 10 explanations for Chad Gadya. I would have expected him at this point to share at least one explanation, but alas, he goes on to explain why Chad Gadya is not diminished by not being recited by the Sefradic Jews.
H/T: I was looking everywhere for this, and was about to give up. As a final attempt, I sent the question to MISSISSIPPI FRED MACDOWELL of On The Main Line, who managed to find it for me, in no time at all!